TREE-KANGAROOS 135 blance to the English hare," and L. leporoides was so called by Gould on account of general appearance as well as face. Dorcopsis has shorter hind-legs than Macropus, and a naked muffle. The ears are small. The structure of D. luctuosa has been studied by Garrod,1 who pointed out the existence of four enlarged hair follicles on the neck near the mandibular sym- physis. These are, however, represented in the next genus Dendrolagus, and occur also in Petrogale. The limbs are not so disproportionate as in Macropus, and the tail is naked at the tip. Dorcopsis and the next genus to be described, Dendrolagus, differ from Macropus and its immediate allies, Petrogale and Lagor- chestes, in a number of anatomical points. In the first place, the premolars are twice the size of those of Macropus, and they have a characteristic pattern not observable in the Kangaroos. This consists of a median ridge (the whole tooth being rather prismatic in shape), with lateral ridges at right angles to it. The upper canines are developed, but are minute. The stomach is not quite like that of Macropus, though built upon a similar plan. The blind cardiac extremity is a single, not a double cul-de-sac.; in this it is like that of Petrogale. The dis- tribution of the squamous, white, oesophageal epithelium is very much like that of Dendrolagus. In both genera the orifice of the oesophagus into the stomach is guarded by two strong longi- tudinal folds, which run for some distance towards the pylorus. In Dendrolagus, at any rate, this tract is bordered on each side by glandular patches. In Dendrolagus, moreover, the squamous epithelium does not extend into the cardiac cul-de-sac. This latter is separated from the rest of the stomach by two slightly diverging folds, which are faintly represented in Petrogale and in ITalinaturus. In the last two genera the folds surrounding the oesophageal orifice are but slightly represented ; better in Hal<ma- turus than in Petrogale. But there are not the patches of glands already referred to. The small intestine of Dorcopsis is 97 inches in length, the large being 32, i.e. proportionately long, as in Marsupials generally. The small caecum (2-^ inches) is not sacculated. The spleen is Macropodine, being T-shaped or Y-shaped. The differences between Dorcopsis and the evidently closely allied Dendrolagus will be further considered under the description of 1 Proc. Zool. Soc. 1875, p. 48.